The coronavirus vaccine rollout has begun in earnest in the UK, but don’t expect to ditch your face mask any time soon.
Sir Patrick Vallance, the government’s chief scientific officer, said he expects life to start “returning towards normal” in spring, but face coverings may be needed until the end of 2021.
“It may be that next winter, even with vaccination, we need measures like masks in place,” he told Sky News. “We don’t know yet how good all the vaccines are going to be at preventing the transmission of the virus.”
But speaking to LBC, Matt Hancock played down the suggestion. Asked if masks would be needed for most of next year, the health secretary said: “I don’t think so,” adding: “I think that by spring we should be out of the measures, I really hope. I hope that we have a normal summer this summer coming.”
Confused? We asked Dr Julian Tang, a consultant virologist and expert in respiratory sciences at the University of Leicester, to explain why the timeline is so unclear – and potentially so long.
Face masks and other social distancing measures will still be needed to protect those who are not yet vaccinated, says Dr Tang. At the moment, we don’t have a clear view on when the vaccine rollout will reach completion.
We also don’t know whether vaccinated people will be asymptomatic – not impacted by the virus themselves but capable of passing it on.
“The recent questions about whether the Covid-19 vaccines can stop onward transmission are interesting and perhaps the main cause of concern here,” he adds. “Normally, vaccine responses are not assessed on the basis of curtailing onward transmission of the virus they are protecting against.
“This is actually very difficult to assess, because you cannot monitor all sources of the virus that might infect any particular individual when the virus is so widespread in the community.”
The question of whether or not a vaccinated person can still spread the virus centres around so-called “sterilising protection”, adds Dr Tang.
“Sterilising protection” would require the vaccine to induce an antibody response and a cell-mediated immune response (a response that doesn’t involve antibodies). This, in theory, would “instantly and completely neutralise any infecting virus” that the vaccinated person is exposed to.
We don’t yet fully know if the vaccine is capable of this, but Dr Tang says the answer is “almost certainly not”.
There will also be a delay in the vaccine’s effectiveness. “The amount of antibodies after vaccination will increase but this will take time – we know from multiple studies that such antibodies take 1-2 weeks to increase and plateau,” Dr Tang says.
“Whilst the immune system is improving and increasing its antibody response to the vaccine, it’s possible that any exposure to the virus may allow some natural infection to occur with viral shedding before the immune response has matured enough to clear any virus completely from the body.”
Scientists are also still uncertain how long immunity will last, from either natural infection or from the vaccines.
“So if someone gradually loses their immunity over time (and we see this with influenza), they may be vulnerable to infection until they get a vaccine boost,” explains Dr Tang. “Until they receive that booster, if they are exposed, then they can become infected and potentially transmit the virus to others then.”
There will be some people who do not respond to the vaccine, adds Dr Tang – another potential delay to life returning to normal.
“As a general rule, we assume that any vaccine will have a 5% failure rate due to natural variations in individual host immune responses, which is why it is useful to have different types of vaccine available for Covid-19,” he says.
“So the masking and social distancing may need to continue until everyone is vaccinated and has mounted a mature, effective immune response to the virus.”
